1. Field of the Invention
This invention is in the field of methods and apparatus for recording TV video signals of an image on photographic film and for reproducing the recorded TV video signals from the information recorded on the film, which information includes a directly viewable reproduction of the image.
2. Description of the Prior Art
Many types of sensing equipment produce TV video signals of images which images are normally displayed by cathode ray tubes (CRT)s. Ultrasonic scanning systems used for conducting medical examinations such as the one disclosed and claimed in an application entitled "High Resolution Rotating Ultrasonic Scanner" by Robert L. Metz et al, Ser. No. 922,185, filed July 5, 1978 application is assigned to the same assignee as this invention, produce large numbers of such images for each patient examined. The abundance of such data creates problems in how to view and properly comprehend the information contained in the images. To do so effectively and efficiently requires that some or all of the images be recorded and retained for an indefinite time. Obviously there is a need to be able to reproduce any images so recorded and retained when desired and to be able to reproduce the images so recorded in any order. These problems are particularly applicable to the medical field where a physician may not be present when the images, cross-sections through an organ of a patient such as a breast, are produced by an ultrasonic scanning system or when the opinion of several specialists may be desired to confirm or establish a diagnosis. Obviously reproducible records from earlier examinations, if available, are particularly helpful in preparing a medical diagnosis as such earlier information can confirm if there has been any observable change and the nature of the change since the last examination or from any earlier examinations. The amount of information available also makes it desirable to reduce the time necessary to interpret individual cross-sectional images of an organ. One way of doing this is by displaying a set of adjacent images sequentially to create a three-dimensional image of the organ in the viewer's mind.
It is also desirable that the record on which the images are stored be compact so that the record of an examination of a patient can be stored in a relatively small space, preferably in the patient's file. It is obviously desirable that the cost of such records be minimized and that the records have the capability of reproducing images of substantially the same quality and detail as the originals when displayed on a TV monitor, for example. It is a great advantage if the records are directly viewable by appropriate optical equipment, similar to a microfiche viewer, so that the image or images so recorded can be viewed and studied other than by displaying them on a CRT of a TV monitor. The capability of being directly viewable is particularly useful in comparing current information displayed on a TV monitor for example with images of the same cross-section obtained in prior examinations.
Prior art devices for recording TV video signals have generally recorded the TV video signals on a magnetic medium such as on magnetic tape or on a magnetic disc. Such magnetic recordings and reproduction systems have the disadvantage of being relatively high in cost, and are characterized by the fact that the images recorded are not directly viewable or perceivable by the human eye or through relatively simple and low cost purely optical viewers. In addition the magnetic media on which such images are stored does not lend itself to the recording of a limited number of images nor for the filing or storing of the records of the images produced in examining one patient, for example, so that all relevant records of the patient are stored in one location and only the records of that patient are stored there.